A cellular mobile communication technology is a technology that provides communication services to wireless devices using an infrastructure, such as a base station. However, since wireless devices become aware of each other and directly send data to each other, a demand for a technology using communication services without requiring an infrastructure, such as a base station, surpasses a demand for a cellular mobile communication technology. In the case of communication services without using an infrastructure, each wireless device may send data to another wireless device via other wireless devices.
Although such a technology is employed, there is a need for a multicast service in which wireless devices having common interest are grouped into a multicast group and data is sent to the wireless devices included in the multicast group.
In the case of communication services using an infrastructure, such as cellular mobile communication, multicast data is sent directly from an infrastructure, such as a base station, to a wireless device, and the management of a multicast group is relatively simple.
However, in the case of communication services without using an infrastructure, multicast data is sent via a plurality of wireless devices. Therefore, there is a difficulty in the management of a multicast group because the multicast group is not maintained even when any one wireless device withdraws from the multicast group.